The present invention relates generally to a method and system for providing adaptive power allocation with selective determination of modulation and coding in a communication system and, more particularly, to a method and system for providing adaptive power allocation with adaptive modulation/coding which provides flexibility to modify the adaptive power allocation method to achieve one or more desired system criteria.
In systems with power control capability, the power of a transmitted signal can be adjusted in order to meet a target signal quality, such as carrier to interference (C/I) ratio or carrier to interference plus noise (C/(Noise+I)) ratio, at the receiver. In such a system, the transmit power will typically be low when a user is close to a base station and will increase with distance from the base station. Unfortunately, with this prior method, a compromise is made between coverage reliability and system capacity. If the system uses a robust form of modulation, such as Binary Phase Shift Keying (B-PSK), good coverage reliability can be obtained, but the system capacity and data rate may be lower than is desired. If, in an attempt to increase data rate and capacity, the system uses a more aggressive form of modulation, such as 8-PSK, the higher C/I requirement cannot be met for all of the users. As a result coverage reliability may be significantly reduced.
Accordingly, there is a need for a method and system which implement adaptive power allocation which achieve relatively high system capacity and system coverage, which provide adaptive modulation/coding capabilities and which provide flexibility to modify the adaptive power allocation method to achieve a number of different system criteria.